An electric motor controller for a steering device that can apply an appropriate steering force to a steering wheel according to running conditions. An electric power steering controller of the present invention includes a steering shaft reaction force torque sensor for detecting a reaction force torque of a steering system, a superimposed reaction force torque calculating unit for multiplying a steering angle detected by the steering angle sensor by a gain to calculate a superimposed reaction force torque in the return direction of the steering wheel, and a control unit for controlling the gain so that the superimposed reaction force torque is reduced when a reaction force torque of the steering system is increased and the superimposed reaction force torque is increased when a reaction force torque of the steering system is decreased.